Cream's stay at the Fillmore Auditorium in the late summer of 1967 was long enough to need two posters. The first, Bonnie MacLean's BG-79, carried the opening run — a bill the Fillmore listings record as the Butterfield Blues Band, Cream and the Southside Sound System, closing on August 27. Cream were the visiting attraction, but on that sheet Paul Butterfield's band was billed above them. The second poster was Jim Blashfield's BG-80, and it took Cream through the rest of the engagement as headliners: Cream, the Electric Flag and vibraphonist Gary Burton, August 29 through September 3.

Tuesday, August 29 was the first night under the new poster and the new billing order.

It is worth being exact about what this run was and wasn't. It was not Cream's first time on an American stage — the trio had made their US debut five months earlier, in March 1967, buried on Murray the K's marathon package shows at the RKO 58th Street Theater in New York, where they played as little as one song, "I'm So Glad," five times a day between other acts. What the Fillmore gave them was the opposite of that: a room, a residency, and an audience that wanted length. Something between fourteen and fifteen hundred people were reportedly packed in for these shows. This is where American audiences met Cream as the band they actually were — Eric Clapton, Jack Bruce and Ginger Baker stretching blues structures past anything a single would allow, for people who had come specifically to hear them do it.

The bill under them was pure Graham. The Electric Flag was Mike Bloomfield's horn-driven outfit, then only months old. Gary Burton, third on the sheet, was a jazz vibraphonist — the kind of pairing that made the Fillmore the Fillmore, and that no other room in the country would have thought to book beneath a British power trio.

One thing the BG-80 sheet does not pin down, and neither will this chronicle. The Electric Flag was not on stage every night of the run. The Fillmore listings note, against each date of the engagement, that "Michael Erlewine's Prime Movers replace The Electric Flag for one of these shows" — and that is the whole of what the record says. Which night it was is not preserved. So the second slot on August 29 is most likely the Electric Flag and possibly the Prime Movers, and the honest version is that one of these late-August nights belonged to Erlewine's band and the surviving lists do not say which.

Across town the same night the Avalon was between weekends, and a year later this same date would belong to a different hall entirely. But August 29, 1967 is Cream's — the first night of Blashfield's poster, at the start of the two-week Fillmore stand that turned a band with a modest American footprint into one San Francisco talked about for the rest of the decade.